Should one use an "other" category in image classification?
It is not advisable because if you use an &quot;other&quot; class, you are just increasing problems for your network. Since &quot;other&quot; means not dog and not cat, then, what common feature does it have? Most of the time the &quot;other&quot; images won't have many features in common. If they do, then go ahead and make an &quot;other&quot; class.
There is a better way: if the probabilities for both cat and dog are less than a threshold (you need to decide that, take, 0.5), then, you can say it is an &quot;other&quot; object.